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Despite researchers considering time of day an important variable in studies on implicit food evaluations and food intake, time of day effects on implicit food evaluations have yet to be tested. Positive implicit evaluations of unhealthy food stimuli measured with an implicit association test (IAT) predict behaviour toward those stimuli, and are assumed to reflect automatic reactions outside of conscious awareness and control. However, recent research has revealed controlled processing to have an influence on IAT performance. The current study tested time of day effects on implicit evaluations of unhealthy food measured with an IAT, and specifically on automatic and controlled processes underlying IAT performance. A sample of 304 undergraduate women aged 17–25 years completed a single-category IAT at varying times of the day. Results revealed that participation later in the day was associated with a more positive implicit evaluation of unhealthy food. This was mediated by a decrease in the ability to inhibit positive food reactions (i.e., controlled processing), rather than an increase in automatic positive reactions. The findings draw attention to the importance of considering time of day in studies measuring aspects of implicit cognition using tasks such as the IAT. [ABSTRACT FROM AUTHOR]

Background The process model proposes that the ego depletion effect is due to (a) an increase in motivation toward indulgence, and (b) a decrease in motivation to control behaviour following an initial act of self-control. In contrast, the reflective-impulsive model predicts that ego depletion results in behaviour that is more consistent with desires, and less consistent with motivations, rather than influencing the strength of desires and motivations. The current study sought to test these alternative accounts of the relationships between ego depletion, motivation, desire, and self-control. Methods One hundred and fifty-six undergraduate women were randomised to complete a depleting e-crossing task or a non-depleting task, followed by a lab-based measure of snack intake, and self-report measures of motivation and desire strength. Results and Conclusions In partial support of the process model, ego depletion was related to higher intake, but only indirectly via the influence of lowered motivation. Motivation was more strongly predictive of intake for those in the non-depletion condition, providing partial support for the reflective-impulsive model. Ego depletion did not affect desire, nor did depletion moderate the effect of desire on intake, indicating that desire may be an appropriate target for reducing unhealthy behaviour across situations where self-control resources vary. [ABSTRACT FROM AUTHOR]

Traditionally, self-control has been conceptualized as the effortful overcoming of desires in order to enact goal-consistent behavior. Several researchers have suggested that instead, self-control is effortless, as individuals with high self-control experience less intense desire that conflicts with valued goals. The current study tested whether the relationship between trait self-control and snack intake was mediated by desire strength, or whether those with higher trait self-control were better able to overcome desire to indulge in unhealthy food, controlling for aspects of the food environment and goal motivation. A sample of women with the goal of eating healthily for weight management ( N = 134) completed a lab-based assessment of snack food consumption and self-report measures of desire strength and trait self-control (generic self-control, and both inhibitory and initiatory subcomponents). As expected, desire strength mediated the relationship between generic self-control and intake, such that higher self-control was related to lower snack intake indirectly via lower desire strength. The relationship between desire and intake was consistent across self-control levels. The same pattern of results emerged for both inhibitory and initiatory self-control. These findings support the contemporary conceptualization of self-control as being effortless due to the reduced strength of unhealthy desires. [ABSTRACT FROM AUTHOR]

The current study used a modified implicit association test (IAT) to change implicit evaluations of unhealthy snack food and tested its effects on subsequent consumption. Furthermore, we investigated whether these effects were moderated by inhibitory self-control. A sample of 148 women (17–25 years) motivated to manage weight through healthy eating completed an IAT intervention, and pre- and post-intervention IATs assessing implicit evaluations of unhealthy food. The intervention IAT trained participants to pair unhealthy food stimuli with either positive or negative stimuli. A task disguised as a taste-test was used to assess consumption of unhealthy snack foods. Inhibitory self-control was measured using a self-report scale. As predicted, the implicit evaluation of unhealthy food became more negative from pre- to post-training among participants in the food negative pairing condition; however, there was no corresponding change in the food positive pairing condition. The effect of the training on snack consumption was moderated by inhibitory self-control with only participants low in inhibitory self-control having lower snack intake following the food negative training. This finding is consistent with dual-process models of behaviour which predict that self-control capacity renders impulses less influential on behaviour. Furthermore, it suggests that an intervention that retrains implicit food evaluations could be effective at reducing unhealthy eating, particularly among those with low inhibitory self-control. [ABSTRACT FROM AUTHOR]

Counteractive control theory suggests that the cognitive accessibility of a goal in response to a temptation cue predicts self-regulation of behaviour consistent with that goal. The current study provided a novel test of this effect in the eating domain, exploring the moderating role of trait self-control. A sample of 124 women (18-25 years) completed a lexical decision task to assess cognitive accessibility of the weight-management goal after food temptation priming. Eating self-regulation was operationalised as unhealthy snack food intake measured in a task disguised as a taste-test. Participants completed trait self-control and temptation experience intensity measures. Cognitive accessibility predicted lower food intake, but only among high self-control participants. The relationship was mediated by temptation experience intensity: participants with high cognitive accessibility felt less tempted, and subsequently ate less food. Results suggest that changing the processes underlying the temptation experience, rather than the cognitive accessibility of a goal may more effectively enhance self-regulation among low self-control individuals. [ABSTRACT FROM AUTHOR]

Portion size impacts on the amount of energy consumed during a meal. However, research findings on participant characteristics that moderate the effect of portion size on energy intake are mixed. Using data pooled across three randomized control trials, we examined the impact of reducing meal portion size on meal energy intake in 111 adult participants varying in sex (55 M, 56 F), body weight (BMI range = 19-42) and a broad range of participant characteristics, including usual portion size, restrained, emotional and external eating, satiety responsiveness, plate clearing tendencies, concerns about wasting food and self-control. In each trial, a repeated-measures design was used and participants consumed three ad-libitum lunchtime meals differing in portion size; large-normal portion size condition (100%) vs. small-normal portion size condition (~ 75%) vs. smaller than normal portion size condition (~ 50%). In mixed ANOVAs, we did not find convincing evidence that any participant characteristic reliably moderated the impact that reducing portion size had on energy intake. For the majority of participants energy intake decreased when portion size was reduced and it was more common for participants to consistently reduce their energy intake than consume a similar amount when portion size was reduced. We also found little evidence that a sub-group of participants existed whose energy intake was consistently resistant to portion size reductions. Portion size may be a universal driver of energy intake, as reducing meal portion size appears to decrease meal energy intake among most people. Food portion downsizing may therefore be an equitable intervention approach to reducing population level energy intake. [ABSTRACT FROM AUTHOR]

Research conducted in controlled laboratory settings plays an important role in understanding human eating behaviour. However, participant characteristics may affect motivation to participate in laboratory eating behaviour research and result in self-selection biases. First-year psychology students (n = 207, 90.8% female, m age = 18.8, m BMI = 21.9) were led to believe that they were choosing between enrolling in one of two laboratory-based studies: an 'advertising' study, or an 'advertising and food' study; the latter specified that participants would consume food and answer questions about their eating behaviour. Participants subsequently reported demographic information and completed a series of questionnaires assessing psychological characteristics hypothesised to predict self-selection in laboratory eating studies. The majority of participants preferred to participate in a study unrelated to eating over an eating-related study (70.5%, χ2 (1) = 34.90, p < .001). Participants choosing the eating-related study over the non-eating study had higher self-reported external eating tendencies and positive preoccupations with food, lower negative preoccupations with food and social appearance anxiety. Participants choosing the eating related study were also more likely to be male than female, although the number of males in the study was small (n = 19) and this finding should therefore be interpreted with caution. The present study provides some evidence that in university based samples of participants there are likely self-selection biases in laboratory-based eating behaviour studies and researchers may benefit from considering the potential influence of self-selection biases when conducting eating behaviour research. [ABSTRACT FROM AUTHOR]